Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Quality of Service (QoS) metrics were originally developed and enhanced for use with switching landline telephony. Such QoS metrics were well characterized and formed an important tool for vendors in providing service. The recent dramatic increase in Voice over IP (VoIP) telephony services has markedly changed landline telephony, and recent 3G/4G advances are making it possible to use a phone's internet connection for VoIP in a mobile environment. Unfortunately, most of these VoIP applications do not include the built-in end-to-end QoS monitoring mechanisms of legacy landline systems, and also lack the industry associations and groups that developed the previous generation of standards for landline systems. Consequently, it may be difficult for users and/or providers to measure the QoS and the overall Quality of Experience (QoE) for VoIP calls on mobile devices.
Watermarking is a common technique that may be used to monitor data degradation. Typically, watermarks are added to a data stream and data degradation may be inferred from changes observed in the watermarks as the data signals transit a network. However, watermarking requires alteration of the data signals and provides for only indirect assessments of data degradation.
Audio or acoustic fingerprinting techniques may be used to characterize and/or protect audio content without requiring alteration of the data signals. An audio fingerprint may provide a condensed digital summary, deterministically generated directly from an audio signal and may generally be used to identify an audio sample or to quickly locate similar items in an audio database.